The present invention generally relates to telecommunications and more specifically to techniques for establishing a connection in a non-relay mode in a communication.
For certain applications it is necessary to be able to establish secure communications between multiple terminals. For example, the U.S. government's secure terminal unit-III (STU-III), NATO's version STU-IIb, and future narrow band digital terminal (FNBDT) are examples of such systems. In a standard network connection, two terminals are connected together across a telephone network. Typically, the telephone network is digital and converts the analog transmissions from a terminal to a digital stream. Once a connection is established between the two terminals, the call switches from a regular voice call to a modem (modulator-demodulator) call. The encrypted voice communications are sent over the modem call.
Typically, the two terminals negotiate with each other to establish a connection. This negotiation involves sending modem tones across the network between the terminals. This process may take a long time depending on how long it takes the modem tones to traverse the network. This method includes many disadvantages. For example, the time it takes two terminals to establish a connection may be long.